This invention relates to an active equalizing circuit having an electronic potentiometer comprising a control network with at least one current controlled circuit.
A large variety of equalization structures are used in transmission processes. For example, "IEEE Transactions on Circuits and Systems", Vol. CAS-29, No. 5, May 1982, page 316-322, FIG. 8, discloses an equalizing structure with a potentiometer according to R. R. Cordell, that is inserted between the output of an operation amplifier and the input clamp of the equalizer structure by connecting the center tap of the potentiometer with the inverting input of the operational amplifier via the series circuit of an emitter follower and a resistor. On one side this inverting input is connected to the input clamp of the equalizing structure, via a series resistance, and, on the other side, it is connected to the output of the operation amplifier via a feedback resistance. Such an equalizer structure with an electronic potentiometer can be used advantageously as an active equalizing circuit. One disadvantage of such an equalizing structure however, is that none of the three electronic potentiometer connections are connected to ground. Furthermore, such ground connections can only be made at a relatively high cost.